Are you planning on flying over the holidays? If you are; now is the time to book your tickets. According to the Airlines Reporting Corporation - a travel industry research group owned by the airlines – the lowest prices for domestic airfares are found eight weeks before the departure date. During that time, fares should be around 19 percent below the average price of $496. The new survey also claims Sunday is the cheapest day to buy plane tickets. As of last Sunday, you have nine weeks until Christmas week.